wifi: mt76: add multi-radio support to scanning code

When scanning on a phy/vif combination that does not have an active link,
create a temporary link in order to ensure that we have a valid wcid.

Link: https://patch.msgid.link/20250102163508.52945-11-nbd@nbd.name


Signed-off-by: Felix Fietkau <nbd@nbd.name>